llvm/lib/Target/PowerPC/PPCInstrInfo.h

//===-- PPCInstrInfo.h - PowerPC Instruction Information --------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the PowerPC implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_POWERPC_PPCINSTRINFO_H
#define LLVM_LIB_TARGET_POWERPC_PPCINSTRINFO_H

#include "PPC.h"
#include "PPCRegisterInfo.h"
#include "llvm/CodeGen/TargetInstrInfo.h"

#define GET_INSTRINFO_HEADER
#include "PPCGenInstrInfo.inc"

namespace llvm {

/// PPCII - This namespace holds all of the PowerPC target-specific
/// per-instruction flags.  These must match the corresponding definitions in
/// PPC.td and PPCInstrFormats.td.
namespace PPCII {
enum {
  // PPC970 Instruction Flags.  These flags describe the characteristics of the
  // PowerPC 970 (aka G5) dispatch groups and how they are formed out of
  // raw machine instructions.

  /// PPC970_First - This instruction starts a new dispatch group, so it will
  /// always be the first one in the group.
  PPC970_First = 0x1,

  /// PPC970_Single - This instruction starts a new dispatch group and
  /// terminates it, so it will be the sole instruction in the group.
  PPC970_Single = 0x2,

  /// PPC970_Cracked - This instruction is cracked into two pieces, requiring
  /// two dispatch pipes to be available to issue.
  PPC970_Cracked = 0x4,

  /// PPC970_Mask/Shift - This is a bitmask that selects the pipeline type that
  /// an instruction is issued to.
  PPC970_Shift = 3,
  PPC970_Mask = 0x07 << PPC970_Shift
};
enum PPC970_Unit {
  /// These are the various PPC970 execution unit pipelines.  Each instruction
  /// is one of these.
  PPC970_Pseudo = 0 << PPC970_Shift,   // Pseudo instruction
  PPC970_FXU    = 1 << PPC970_Shift,   // Fixed Point (aka Integer/ALU) Unit
  PPC970_LSU    = 2 << PPC970_Shift,   // Load Store Unit
  PPC970_FPU    = 3 << PPC970_Shift,   // Floating Point Unit
  PPC970_CRU    = 4 << PPC970_Shift,   // Control Register Unit
  PPC970_VALU   = 5 << PPC970_Shift,   // Vector ALU
  PPC970_VPERM  = 6 << PPC970_Shift,   // Vector Permute Unit
  PPC970_BRU    = 7 << PPC970_Shift    // Branch Unit
};

enum {
  /// Shift count to bypass PPC970 flags
  NewDef_Shift = 6,

  /// The VSX instruction that uses VSX register (vs0-vs63), instead of VMX
  /// register (v0-v31).
  UseVSXReg = 0x1 << NewDef_Shift,
  /// This instruction is an X-Form memory operation.
  XFormMemOp = 0x1 << (NewDef_Shift+1)
};
} // end namespace PPCII

// Instructions that have an immediate form might be convertible to that
// form if the correct input is a result of a load immediate. In order to
// know whether the transformation is special, we might need to know some
// of the details of the two forms.
struct ImmInstrInfo {
  // Is the immediate field in the immediate form signed or unsigned?
  uint64_t SignedImm : 1;
  // Does the immediate need to be a multiple of some value?
  uint64_t ImmMustBeMultipleOf : 5;
  // Is R0/X0 treated specially by the original r+r instruction?
  // If so, in which operand?
  uint64_t ZeroIsSpecialOrig : 3;
  // Is R0/X0 treated specially by the new r+i instruction?
  // If so, in which operand?
  uint64_t ZeroIsSpecialNew : 3;
  // Is the operation commutative?
  uint64_t IsCommutative : 1;
  // The operand number to check for load immediate.
  uint64_t ConstantOpNo : 3;
  // The operand number for the immediate.
  uint64_t ImmOpNo : 3;
  // The opcode of the new instruction.
  uint64_t ImmOpcode : 16;
  // The size of the immediate.
  uint64_t ImmWidth : 5;
  // The immediate should be truncated to N bits.
  uint64_t TruncateImmTo : 5;
};

// Information required to convert an instruction to just a materialized
// immediate.
struct LoadImmediateInfo {
  unsigned Imm : 16;
  unsigned Is64Bit : 1;
  unsigned SetCR : 1;
};

class PPCSubtarget;
class PPCInstrInfo : public PPCGenInstrInfo {
  PPCSubtarget &Subtarget;
  const PPCRegisterInfo RI;

  void StoreRegToStackSlot(MachineFunction &MF, unsigned SrcReg, bool isKill,
                           int FrameIdx, const TargetRegisterClass *RC,
                           SmallVectorImpl<MachineInstr *> &NewMIs) const;
  void LoadRegFromStackSlot(MachineFunction &MF, const DebugLoc &DL,
                            unsigned DestReg, int FrameIdx,
                            const TargetRegisterClass *RC,
                            SmallVectorImpl<MachineInstr *> &NewMIs) const;
  bool transformToImmForm(MachineInstr &MI, const ImmInstrInfo &III,
                          unsigned ConstantOpNo, int64_t Imm) const;
  MachineInstr *getConstantDefMI(MachineInstr &MI, unsigned &ConstOp,
                                 bool &SeenIntermediateUse) const;
  const unsigned *getStoreOpcodesForSpillArray() const;
  const unsigned *getLoadOpcodesForSpillArray() const;
  virtual void anchor();

protected:
  /// Commutes the operands in the given instruction.
  /// The commutable operands are specified by their indices OpIdx1 and OpIdx2.
  ///
  /// Do not call this method for a non-commutable instruction or for
  /// non-commutable pair of operand indices OpIdx1 and OpIdx2.
  /// Even though the instruction is commutable, the method may still
  /// fail to commute the operands, null pointer is returned in such cases.
  ///
  /// For example, we can commute rlwimi instructions, but only if the
  /// rotate amt is zero.  We also have to munge the immediates a bit.
  MachineInstr *commuteInstructionImpl(MachineInstr &MI, bool NewMI,
                                       unsigned OpIdx1,
                                       unsigned OpIdx2) const override;

public:
  explicit PPCInstrInfo(PPCSubtarget &STI);

  /// getRegisterInfo - TargetInstrInfo is a superset of MRegister info.  As
  /// such, whenever a client has an instance of instruction info, it should
  /// always be able to get register info as well (through this method).
  ///
  const PPCRegisterInfo &getRegisterInfo() const { return RI; }

  bool isXFormMemOp(unsigned Opcode) const {
    return get(Opcode).TSFlags & PPCII::XFormMemOp;
  }

  ScheduleHazardRecognizer *
  CreateTargetHazardRecognizer(const TargetSubtargetInfo *STI,
                               const ScheduleDAG *DAG) const override;
  ScheduleHazardRecognizer *
  CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II,
                                     const ScheduleDAG *DAG) const override;

  unsigned getInstrLatency(const InstrItineraryData *ItinData,
                           const MachineInstr &MI,
                           unsigned *PredCost = nullptr) const override;

  int getOperandLatency(const InstrItineraryData *ItinData,
                        const MachineInstr &DefMI, unsigned DefIdx,
                        const MachineInstr &UseMI,
                        unsigned UseIdx) const override;
  int getOperandLatency(const InstrItineraryData *ItinData,
                        SDNode *DefNode, unsigned DefIdx,
                        SDNode *UseNode, unsigned UseIdx) const override {
    return PPCGenInstrInfo::getOperandLatency(ItinData, DefNode, DefIdx,
                                              UseNode, UseIdx);
  }

  bool hasLowDefLatency(const TargetSchedModel &SchedModel,
                        const MachineInstr &DefMI,
                        unsigned DefIdx) const override {
    // Machine LICM should hoist all instructions in low-register-pressure
    // situations; none are sufficiently free to justify leaving in a loop
    // body.
    return false;
  }

  bool useMachineCombiner() const override {
    return true;
  }

  /// Return true when there is potentially a faster code sequence
  /// for an instruction chain ending in <Root>. All potential patterns are
  /// output in the <Pattern> array.
  bool getMachineCombinerPatterns(
      MachineInstr &Root,
      SmallVectorImpl<MachineCombinerPattern> &P) const override;

  bool isAssociativeAndCommutative(const MachineInstr &Inst) const override;

  bool isCoalescableExtInstr(const MachineInstr &MI,
                             unsigned &SrcReg, unsigned &DstReg,
                             unsigned &SubIdx) const override;
  unsigned isLoadFromStackSlot(const MachineInstr &MI,
                               int &FrameIndex) const override;
  bool isReallyTriviallyReMaterializable(const MachineInstr &MI,
                                         AliasAnalysis *AA) const override;
  unsigned isStoreToStackSlot(const MachineInstr &MI,
                              int &FrameIndex) const override;

  bool findCommutedOpIndices(MachineInstr &MI, unsigned &SrcOpIdx1,
                             unsigned &SrcOpIdx2) const override;

  void insertNoop(MachineBasicBlock &MBB,
                  MachineBasicBlock::iterator MI) const override;


  // Branch analysis.
  bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
                     MachineBasicBlock *&FBB,
                     SmallVectorImpl<MachineOperand> &Cond,
                     bool AllowModify) const override;
  unsigned removeBranch(MachineBasicBlock &MBB,
                        int *BytesRemoved = nullptr) const override;
  unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
                        MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
                        const DebugLoc &DL,
                        int *BytesAdded = nullptr) const override;

  // Select analysis.
  bool canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
                       unsigned, unsigned, int &, int &, int &) const override;
  void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
                    const DebugLoc &DL, unsigned DstReg,
                    ArrayRef<MachineOperand> Cond, unsigned TrueReg,
                    unsigned FalseReg) const override;

  void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                   const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
                   bool KillSrc) const override;

  void storeRegToStackSlot(MachineBasicBlock &MBB,
                           MachineBasicBlock::iterator MBBI,
                           unsigned SrcReg, bool isKill, int FrameIndex,
                           const TargetRegisterClass *RC,
                           const TargetRegisterInfo *TRI) const override;

  void loadRegFromStackSlot(MachineBasicBlock &MBB,
                            MachineBasicBlock::iterator MBBI,
                            unsigned DestReg, int FrameIndex,
                            const TargetRegisterClass *RC,
                            const TargetRegisterInfo *TRI) const override;

  unsigned getStoreOpcodeForSpill(unsigned Reg,
                                  const TargetRegisterClass *RC = nullptr) const;

  unsigned getLoadOpcodeForSpill(unsigned Reg,
                                 const TargetRegisterClass *RC = nullptr) const;

  bool
  reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;

  bool FoldImmediate(MachineInstr &UseMI, MachineInstr &DefMI, unsigned Reg,
                     MachineRegisterInfo *MRI) const override;

  // If conversion by predication (only supported by some branch instructions).
  // All of the profitability checks always return true; it is always
  // profitable to use the predicated branches.
  bool isProfitableToIfCvt(MachineBasicBlock &MBB,
                          unsigned NumCycles, unsigned ExtraPredCycles,
                          BranchProbability Probability) const override {
    return true;
  }

  bool isProfitableToIfCvt(MachineBasicBlock &TMBB,
                           unsigned NumT, unsigned ExtraT,
                           MachineBasicBlock &FMBB,
                           unsigned NumF, unsigned ExtraF,
                           BranchProbability Probability) const override;

  bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
                                 BranchProbability Probability) const override {
    return true;
  }

  bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
                                 MachineBasicBlock &FMBB) const override {
    return false;
  }

  // Predication support.
  bool isPredicated(const MachineInstr &MI) const override;

  bool isUnpredicatedTerminator(const MachineInstr &MI) const override;

  bool PredicateInstruction(MachineInstr &MI,
                            ArrayRef<MachineOperand> Pred) const override;

  bool SubsumesPredicate(ArrayRef<MachineOperand> Pred1,
                         ArrayRef<MachineOperand> Pred2) const override;

  bool DefinesPredicate(MachineInstr &MI,
                        std::vector<MachineOperand> &Pred) const override;

  bool isPredicable(const MachineInstr &MI) const override;

  // Comparison optimization.

  bool analyzeCompare(const MachineInstr &MI, unsigned &SrcReg,
                      unsigned &SrcReg2, int &Mask, int &Value) const override;

  bool optimizeCompareInstr(MachineInstr &CmpInstr, unsigned SrcReg,
                            unsigned SrcReg2, int Mask, int Value,
                            const MachineRegisterInfo *MRI) const override;

  /// GetInstSize - Return the number of bytes of code the specified
  /// instruction may be.  This returns the maximum number of bytes.
  ///
  unsigned getInstSizeInBytes(const MachineInstr &MI) const override;

  void getNoop(MCInst &NopInst) const override;

  std::pair<unsigned, unsigned>
  decomposeMachineOperandsTargetFlags(unsigned TF) const override;

  ArrayRef<std::pair<unsigned, const char *>>
  getSerializableDirectMachineOperandTargetFlags() const override;

  ArrayRef<std::pair<unsigned, const char *>>
  getSerializableBitmaskMachineOperandTargetFlags() const override;

  // Expand VSX Memory Pseudo instruction to either a VSX or a FP instruction.
  bool expandVSXMemPseudo(MachineInstr &MI) const;

  // Lower pseudo instructions after register allocation.
  bool expandPostRAPseudo(MachineInstr &MI) const override;

  static bool isVFRegister(unsigned Reg) {
    return Reg >= PPC::VF0 && Reg <= PPC::VF31;
  }
  static bool isVRRegister(unsigned Reg) {
    return Reg >= PPC::V0 && Reg <= PPC::V31;
  }
  const TargetRegisterClass *updatedRC(const TargetRegisterClass *RC) const;
  static int getRecordFormOpcode(unsigned Opcode);

  bool isTOCSaveMI(const MachineInstr &MI) const;

  bool isSignOrZeroExtended(const MachineInstr &MI, bool SignExt,
                            const unsigned PhiDepth) const;

  /// Return true if the output of the instruction is always a sign-extended,
  /// i.e. 0 to 31-th bits are same as 32-th bit.
  bool isSignExtended(const MachineInstr &MI, const unsigned depth = 0) const {
    return isSignOrZeroExtended(MI, true, depth);
  }

  /// Return true if the output of the instruction is always zero-extended,
  /// i.e. 0 to 31-th bits are all zeros
  bool isZeroExtended(const MachineInstr &MI, const unsigned depth = 0) const {
   return isSignOrZeroExtended(MI, false, depth);
  }

  bool convertToImmediateForm(MachineInstr &MI,
                              MachineInstr **KilledDef = nullptr) const;
  void replaceInstrWithLI(MachineInstr &MI, const LoadImmediateInfo &LII) const;

  bool instrHasImmForm(const MachineInstr &MI, ImmInstrInfo &III) const;
};

}

#endif